U.S. patent number 5,667,737 [Application Number 08/614,319] was granted by the patent office on 1997-09-16 for method of manufacturing an injection molded shoe.
This patent grant is currently assigned to Koflach Sport Gesellschaft m.b.H. & Co. KG. Invention is credited to Walter Wittmann.
United States Patent |
5,667,737 |
Wittmann |
September 16, 1997 |
Method of manufacturing an injection molded shoe
Abstract
A sport shoe or boot comprises an integral outer shoe including
a plurality of shaped portions of at least two different synthetic
resin materials, adjacent portions of different synthetic resin
materials being interconnected in overlapping transition areas
shaped to fit each other. The outer shoe is manufactured by
injecting the different synthetic resin materials in plasticized
condition and at staggered intervals into a mold cavity at
pre-selected portions thereof, permitting the injected synthetic
resin materials to harden in the mold cavity to form the integral
outer shoe, and removing the outer shoe from the mold cavity.
Inventors: |
Wittmann; Walter (Koflach,
AT) |
Assignee: |
Koflach Sport Gesellschaft m.b.H.
& Co. KG (Wagrain, AT)
|
Family
ID: |
3483696 |
Appl.
No.: |
08/614,319 |
Filed: |
March 12, 1996 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
166507 |
Dec 13, 1993 |
|
|
|
|
47878 |
Apr 15, 1993 |
|
|
|
|
825934 |
Jan 27, 1992 |
|
|
|
|
Foreign Application Priority Data
Current U.S.
Class: |
264/40.1;
264/245; 264/255; 264/328.8; 425/129.2; 425/130 |
Current CPC
Class: |
A43B
1/0027 (20130101); A43B 5/04 (20130101); A43B
5/049 (20130101); B29D 35/04 (20130101); B29D
35/14 (20130101); B29D 35/146 (20130101); A43B
23/0215 (20130101); A43B 23/0225 (20130101) |
Current International
Class: |
A43B
5/04 (20060101); B29D 31/505 (20060101); B29D
31/518 (20060101); B29D 31/50 (20060101); B29C
045/13 (); B29C 045/16 () |
Field of
Search: |
;264/244,245,255,328.8,294,40.1,40.4 ;425/129.1,129.2,130 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
95.015 |
|
Mar 1970 |
|
FR |
|
1933570 |
|
Jan 1971 |
|
DE |
|
26 36 355 |
|
Feb 1978 |
|
DE |
|
30 24 808 |
|
Dec 1981 |
|
DE |
|
1020801 |
|
Jan 1989 |
|
JP |
|
1005502 |
|
Jan 1989 |
|
JP |
|
623 463 |
|
Jun 1981 |
|
CH |
|
Primary Examiner: Ortiz; Angela
Attorney, Agent or Firm: Collard & Roe, P.C.
Parent Case Text
This is a continuation of application Ser. No. 08/166,507 filed on
Dec. 13, 1993, now abandoned which is a divisional of Ser. No.
08/047,878 filed Apr. 15, 1993, now abandoned, which is a
continuation of Ser. No. 07/825,934, filed Jan. 27, 1992, now
abandoned.
Claims
What is claimed is:
1. A method for manufacturing an integrally-formed injection molded
shoe article, comprising the steps of:
coupling a distributing valve to a first extruder and a second
extruder;
connecting a control device comprising a microprocessor to said
first extruder, said second extruder and said distributing
valve;
coupling a plurality of sprues of a mold to a corresponding
plurality of outlets of said distributing valve via respective
supply conduits;
plasticizing a first synthetic resin material in the first extruder
and a second different synthetic resin material in the second
extruder;
controlling the length of time of actuation of each of said first
and second extruders, with said control device, to produce
different pressures in said extruders;
operating said distributing valve with said control device, to (i)
select at least one outlet and corresponding supply conduit for
successively receiving the first and second synthetic resin
materials and (ii) control the length of time for said at least one
selected outlet and corresponding supply conduit to successively
receive the first and second synthetic resin materials;
injecting the first and second synthetic resin materials
successively through the respective sprue into the mold cavity so
that the molten first and second synthetic resin materials flow
into each other;
wherein the different synthetic resin materials are injected into
the mold cavity at different pressures;
wherein at least one of the different synthetic resin materials is
injected into the mold cavity at a pressure which varies during the
injection of the synthetic resin material;
permitting the injected synthetic resin materials to harden in the
mold cavity and permanently bond together to form an integral
injection molded shoe article; and
removing the shoe article from the mold cavity.
2. The manufacturing method of claim 1, wherein the lengths of time
during which each of the different synthetic resin materials is
injected into the mold cavity differ from each other.
3. The manufacturing method of claim 2 wherein the lengths of the
injection times are separately controlled by controlling said
distributing valve accordingly.
4. The manufacturing method of claim 1, further comprising the
steps of programming the operation of said first and second
extruders and said distributing valve.
5. The manufacturing method of claim 4, wherein the different
synthetic resin materials are alternately introduced into each of
two conduits for injection through two sprues into the mold cavity.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a shoe comprising an outer shoe of
synthetic resin material, and to a method of manufacturing an outer
shoe.
2. Description of the Prior Art
A great variety of shoes, particularly ski, ice skating, ice
hockey, mounting climbing and work boots, are known, which comprise
an outer shoe or shell comprised completely or partly of synthetic
resin material. The outer shoe holds the closure devices and an
inner shoe into which the foot of the wearer fits. Such outer shoes
are sometimes made of several individual parts but usually they are
made of a shell and a shank comprised of a single synthetic resin
material which imparts the same appearance to the entire outer
shoe. However, the shell and the shaft, or individual parts riveted
or bonded thereto, may be comprised of different synthetic resin
materials having a different appearance or color, for example, or
partially reinforcing the shell or the shank, or better adapting
them to environmental conditions. However, in these known outer
shoes, the individual parts must be riveted or bonded to the outer
shoe or the outer shoe must be assembled from such individual
parts. This increases the production cost and requires a
considerable inventory of individual parts to be stored, which
tends to raise the price of such shoes.
SUMMARY OF THE INVENTION
It is the primary object of this invention to provide an integral
outer shoe, or an integral part of an outer shoe, which may be
readily adapted to a variety of customer requirements without
disadvantageously changing the production costs.
The above and other objects are accomplished according to the
invention with an integral outer shoe, or an integral part of an
outer shoe, including a plurality of shaped portions of at least
two different synthetic resin materials, adjacent portions of
different synthetic resin materials being interconnected in
overlapping transition areas shaped to fit each other.
This seemingly simple solution has the surprising advantage that
the combined use of different synthetic resin materials makes it
possible to meet all types of customer demands without requiring
the manufacture of a large number of different parts. Only a single
part or outer shoe need be stored in inventory. It has the further
advantage that such products may be exactly reproduced, which makes
additional productions possible at short notice if there is further
demand for the product. By suitably choosing the colors,
UV-resistance and other properties of the different synthetic resin
materials, the outer shoes may be tailored to any desired use. For
example, by selecting colors that respond differently to varying
temperatures for different portions or layers of the outer shoe or
outer shoe part, it is possible to equalize extension modulus of
the outer shoe of a ski boot and to reduce the stress on the outer
shoe when subjected to severe temperatures. It is also possible to
use synthetic resin materials of higher mechanical strength at
predetermined portions of the outer shoe so that they may be
equipped, for example, with pivots or the like.
If the portions of different synthetic resin materials are
connected to each other in a plasticized condition, tears in the
transition areas will be prevented. Hardening the portions
simultaneously will prevent hairline cracks during cooling of the
molded shoe portions as well as breaks under stress during wear of
the shoe. The designs of the portions may be freely selected.
According to one feature of this invention, adjacent portions of
two different synthetic resin materials alternate with each other
so as to produce a uniform distribution. The adjacent portions may
be superposed layers of different synthetic resin materials.
The synthetic resin materials may differ in composition and/or in
color whereby the different portions of the shoe may be simply
adjusted to their respective use requirements. If the synthetic
resin materials differ in their mechanical properties, such as
impact resistance, hardness or resistance to ultraviolet radiation,
the more expensive synthetic resin materials meeting these
requirements may be limited to those portions of the outer shoe
where they are actually needed.
Reinforcing elements may be provided in at least some of the shaped
portions to provide desirable reinforcements of the mechanical
properties of the synthetic resin material used in such portions.
The reinforcing elements may be embedded in the synthetic resin
portions so that the appearance of the outer shoe will not be
changed thereby.
The shoe may be a ski boot, for example, wherein the outer shoe
comprises a shell and a movable shank adjustable relative to the
shell, the shaped portions of different synthetic materials being
substantially uniformly distributed over the shell and shank. Such
a shoe will have uniform strength.
According to another aspect of the invention, an integral outer
shoe of the indicated type is manufactured by injecting the
different synthetic resin materials in plasticized condition and at
staggered intervals into a mold cavity at pre-selected portions
thereof, permitting the injected synthetic resin materials to
harden in the mold cavity to form the integral outer shoe, and
removing the outer shoe from the mold cavity. The positioning of
the portions of different synthetic resin materials in the mold
cavity will be facilitated by the staggered timing of the injection
of the materials.
According to one feature of the manufacturing method, the different
synthetic materials are injected into the mold cavity at different
pressures. In this way, surface layers of different synthetic resin
materials may be produced on layers of synthetic resin materials
previously injected into the mold cavity. If at least one of the
different synthetic resin materials is injected into the mold
cavity at pressures which vary during the injection of the
material, the layers of different synthetic resin materials will be
seamlessly laminated to each other to form an integral shaped
portion.
According to another preferred feature of the manufacturing method,
the lengths of time during which each of the different synthetic
resin materials is injected into the mold cavity differ from each
other and the injection times are preferably separately controlled
whereby the magnitude of the portions of different synthetic resin
materials may be determined in a simple manner and thus be adapted
to various use requirements.
BRIEF DESCRIPTION OF THE DRAWING
The above and other objects, advantages and features of the present
invention will become more apparent from the following detailed
description of certain now preferred embodiments thereof, taken in
conjunction with the accompanying drawing wherein
FIG. 1 is a side elevational view of a shoe illustrated as a ski
boot comprising an outer shoe according to this invention;
FIG. 2 is a sectional end view of the shoe, taken along line II--II
of FIG. 1;
FIGS. 3 and 4 are like views showing two additional embodiments
with differently arranged layers of different synthetic resin
materials;
FIG. 5 is a like enlarged, fragmentary view showing reinforcing
elements in portions and transition areas of the outer shoe;
and
FIG. 6 schematically illustrates a plant for manufacturing outer
shoes according to the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring first to FIG. 1, the illustrated shoe is a ski boot
comprising integral outer shoe 1 including shell 2 with shank 3
pivotal about axis 4. To close the shoe, outer shoe shell 2 and
shank 3 carry buckles 5. Inner shoe 6 is arranged inside outer shoe
1. To adapt to the personal needs of individual wearers, ski boot 1
has adjustment devices 7. Ski boots of this general construction
are well known and since this general construction forms no part of
the present invention, it is not further described in detail.
As shown in the drawing, outer shoe shell 2 and its shank 3 include
a plurality of shaped portions 8, 9, 10, 11 of at least two
different synthetic resin materials 12, 13, adjacent portions of
different synthetic resin materials being interconnected in
overlapping transition areas 16 shaped to fit each other, as shown
in FIG. 2. The illustrated adjacent portions of two different
synthetic resin materials alternate with each other. In the
embodiments shown in FIGS. 3 and 4, the adjacent portions are
superposed layers 17, 18, 19 of different synthetic resin
materials.
Synthetic resin materials 12, 13 may differ in composition and/or
in color and/or in their mechanical properties, such as impact
resistance, hardness or resistance to ultraviolet radiation. For
example, synthetic resin materials 12, 13 may be comprised of the
same synthetic resin having the same mechanical properties but
being differently colored so as to assume thereby different
strengths and other properties of wear under the influence of
UV-radiation and/or changes of temperature. Thus, the portions of
the outer shoe act differently under different temperatures because
of their different colors so that they stretch differently to
adjust the total stretch of the outer shoe to a desired value. In
this way, some of the shoe portions will warm up more than other
portions so that tensions between the adjacent shoe portions will
be equalized.
It is, of course, also possible to use synthetic resin materials
12, 13 of different mechanical or physical properties in portions 8
to 11. Thus, the materials may be so selected that they assume
different colors at varying temperatures or that adjacent portions
have different colors at the same temperature. On the other hand,
if synthetic resin materials 12, 13 of different impact resistance
or elasticity are used, for example, the outer shoe will be adapted
more sensitively to various areas of the foot of the wearer. For
instance, in portion 11 where pivot 4 is located, synthetic resin
material 13 may have a greater strength and rigidity while
synthetic material 12 in ankle portion 14 of the outer shoe has a
greater elasticity to avoid pressure on the foot of the wearer. It
may also be advantageous to use synthetic resin materials of higher
ultraviolet radiation resistance in horizontally extending shoe
portions than in vertically extending portions.
If shoe 1 is a work boot, it may be advantageous to make tip
portion 15 of the shoe of a synthetic resin material 12 which is
more deformable and is resistant to penetration.
If desired, more than two different synthetic resin materials may
be used for outer shoe portions 8 to 11, 14 and 17 to 19.
As shown in FIG. 2, adjacent portions 9 to 11 of different
synthetic resin materials 12, 13 are interconnected in overlapping
transition areas 16 shaped to fit each other. This fit at the
transition areas is obtained by charging the synthetic resin
materials in plasticized condition into a mold cavity and
permitting them to cool therein simultaneously so that the seams
between the adjacent portions harden into an integral structure.
This produces a very firm connection between the adjacent portions
of different synthetic resin materials and a more or less
homogenous transition between different synthetic resin materials
12, 13 with transitional zones of tension. The simultaneous cooling
and hardening of all the outer shoe portions in the mold cavity
will impart to outer shoe 2 and shank 3 a very high strength.
FIG. 3 illustrates an embodiment wherein the outer shoe is
comprised of a base layer portion 18 of synthetic resin material 12
and superposed layer portions 17 of different synthetic resin
material 12 embedded in the base layer portion. This enables the
shoe to be partially reinforced along spaced surface areas
subjected to the greater stress during wear.
In the embodiment of FIG. 4, the outer shoe is comprised of base
layer portion 19 of synthetic material 20 and superposed layer
surface layer portions 17', 18' of different synthetic resin
materials extending over the entire surface of the base layer
portion so that the entire outer shoe is of a multi-layer
structure. Portions 17', 18' adjacent to portion 19 as well as
portions 17', 18' adjacent to each other are interconnected in
overlapping transition areas shaped to fit each other, and surface
layer portions 17', 18' are laminated to base layer portion 19. The
laminated outer shoe structure has a thickness 22 defined by
thickness 21 of surface layer portions 17', 18' and thickness 23 of
base layer portion 19. The extension of the individual surface
layer portions and their positioning is freely selectable and may
be predetermined by suitably controlling the molding process
illustrated in FIG. 6 and described hereinafter.
FIG. 5 schematically illustrates an embodiment wherein reinforcing
elements 24, 25 are provided in at least some of the shaped
portions of the outer shoe. As shown in the drawing, reinforcing
element 24 is embedded in shoe portion 10. This may be a fibrous
web or net of suitable filaments, for example of glass, carbon or
ceramic, which is extruded with the synthetic material forming the
reinforced portion. As also shown in the drawing, it is also
possible to arrange a reinforcing element 25 in a transition area
between shoe portions 8 and 9. Equivalently, it is also possible to
embed such reinforcing elements between the layer portions of the
outer shoe illustrated in FIGS. 3 and 4. If the manufacturing
method permits, metallic reinforcing elements may also be used, for
example for reinforcing tip portion 15 of work boots.
The method of manufacturing the integral outer shoe of the
invention is illustrated in FIG. 6. As shown, shoe 1 is
manufactured in mold 26 defining mold cavity 27. Sprues 28, 29, 30
lead into mold cavity 27 and are connected to extruders 31, 32 for
plasticizing synthetic resin materials 33, 34 so that the synthetic
resin materials are injected into the mold cavity in plasticized
condition. Distributing valve 35 is arranged in the conduits
leading from the outputs of extruders 31, 32 to sprues 28, 29, 30
for distributing the plasticized synthetic resin materials into
mold cavity 27 at pre-selected portions thereof. Synthetic resin
materials 33, 34 are stored in suitable hoppers in granulated form
for feeding into the extruders.
Extruders 31, 32 are driven by motors 36, 36 whose operation is
controlled by control device 37 which includes timer 38, adjustment
elements 39 and input terminal 40 which may comprise a
microprocessor. The adjustment elements 39 and input terminal 40
enable the operation of extruder drive motors 36 to be programmed
so that the drive motors may be actuated for different lengths of
time, for example alternately, simultaneously or to produce
different pressures in the extruders. Correspondingly, distributor
valve 35 will determine at what staggered time intervals and at
what portions of mold cavity 27, i.e. through which sprue 28, 29,
30, the synthetic resin materials plasticized in extruders 31, 32
will be injected. For example, if the plasticized synthetic resin
fluids are alternately injected through sprue 28 and/or 30, the
synthetic resins will be injected into mold cavity 27 in planes
causing shoe portions 8 to 11 or layers 17 to 19 to be formed
successively in the mold cavity where the successive portions or
layers will melt into each other. If the plasticized synthetic
resin material is injected through sprue 29, the superposed layers
will extend substantially parallel to the sole.
A number of variations of the injection of the plasticized
synthetic resin materials into the mold cavity are conceivable, for
example injection through a plurality of sprues in different
directions alternatingly, simultaneously, successively and
overlappingly. For instance, layer portions 17 to 19 may be
produced by first injecting the plasticized synthetic resin
material for base layer portion 19 and then injecting synthetic
resin materials under a pressure exceeding that prevailing in mold
cavity 27 to laminate layer portions 17, 18 to base layer portion
19.
Since the injected synthetic resin materials will flow into each
other at their interfaces so that a fluid transition area is
produced between adjacent portions or layers, different synthetic
resin materials 12, 13 will mesh into each other and thus produce a
permanent bonding therebetween upon hardening of the synthetic
resin material portions in the mold cavity to form integral outer
shoe 1. After hardening, the outer shoe is removed from the mold
cavity. No cracks or breaks will appear in the transition areas
between the different synthetic resin materials.
It should be noted that the present invention may be usefully
applied not only to ski boots, as described by way of example, but
to all types of shoes and boots which comprise outer shoes of
synthetic resin material. Also, if desired, parts of such outer
shoes may be manufactured in this fashion so that wherever the
specification and the claims refer to an "outer shoe" this term
includes a part of an outer shoe.
Useful synthetic resins for molding the outer shoe include
Polyurethane, Polypropylene, Polyamide, preferably Polyurethane
with an admixture of UV-radiation resistant materials include
UV-stabilizer. By way of example up to 5% colored granulated
material is admixted to synthetic resin material for purpose of
coloration.
To carry out the method of manufacturing a ski boot according to
the invention, two extruders with several nozzles connected to the
mold cavity are connected in series. According to another
embodiment of carrying out the manufacturing method, a two-worm
machine with a nozzle equipped with two independently operable
closures may be used. With a conventional interval injection
molding method, the two extruders or worms are alternately operated
after the start. They alternately injection-mold in intervals until
the outer skin of the ski boot has been supplied with sufficient
material. Thereupon, the core is filled without interval by both
extruders or worms. Each nozzle associated with a worm is operated
simultaneously with the extruder worms.
The technical parameters, such as operating times, pressures,
intervals, temperatures, depend on the shapes, sizes, material and
color. For example, the following technical parameters apply to a
ski boot of size 275 mm corresponding to the length of the sole,
for the material designated API 191:
Cycle time: 150 seconds
Injection time: 8 seconds
After-pressure time: 50 seconds
Cooling time: 70 seconds
Injection pressure: 100 bar
After-pressure: 30 bar
Temperature of the mass: 210.degree. C.
Removal temperature: 70.degree. C.
The indicated injection time of 8 seconds is the total sum of, for
example, two nozzles filling the mold cavity in an interval method,
including the intervals during which the material flow through the
nozzles is interrupted.
* * * * *